3
3-3 System Description - Strider Receiver Link
Strider Link Series
SRFStrider-161004A-REV.A
Sinteck Sistemas Eletrônicos Ltda.
The Strider Link Receiver series has two different types of receivers which are designed for
different RF environments. The most popular version is the “Link Receiver” that is a single-
conversion receiver that provides maximum performance in all but the most demanding
environments. The model “Triple-C Link Receiver” is triple-conversion receiver which
provide maximum out-of-band and adjacent channel protection. The Triple-C exhibits
superior front end performance in the presence of extremely strong RF fields, as it uses
modules from the time-proven Sinteck Next.
Both systems are selectable to support mono or composite operation. The receivers are
single in construction and operation, just one PC board, and the system description given
below follows the signal flow in the block diagrams referenced above.
The model “Triple-C Link Receiver” is not explained in this manual.
The system assembly drawings are located in section “ schematics” along with the
module schematics and assembly drawings. The system block diagrams and system
schematics are at the end of this manual.
Preselector/Preamplifier - Front End
The Preselector/Preamplifier is located out of the main PC board of the receiver. The
antenna input signal is first passed through the preselector filter section, which is a three-
element helical bandpass filter with a 5MHz bandwidth with very low insertion loss. The
output of the preselector filter is fed to the preamplifier providing low-noise gain. The
postselector filter provides further filtering as well as image noise rejection.
Preselector Filter and Booster
A second filter located on the preselector filter consists in other RF filter and amplifier
presenting high gain and low distortion.
Preamplifier
The output of the Booster is fed to the preamplifier on the RF section of the receiver. This
preamplifier incorporates an adjustable gain circuit and schockty barrier diodes attenuators
for user-adjustable front end protection and isolation. The low noise, high-intercept point
preamplifier is followed by the image noise filter.
Local Oscillator
The Local Oscillator consists of a 170-450MHz ultralinear, very low noise VCO which is
phase locked to a crystal-controlled reference oscillator. The phase lock loop contains the
frequency programming mode which allow the synthesizer to be changed in frequency
steps of 250kHz (standard) 25kHz or 100kHz in some models.
Mixer and IF Demod
The mixer and IF Demod are located together the same component. A modern IC does the
both functions with the best performance. The carrier frequency provenient from the
Oscillator is mixed into the IC with the antenna signal to provide down direct-convesion to
the 10,7Mhz Intermediary Frequency. The IF is buffered to overcome mixer conversion loss.
The IF Demod module provides down conversion to the 10,7MHz, sets system selectivity in
this IF, extracts the baseband information from the carrier, provides the logarithmic RF
signal strength voltage for metering, and establishes the mute threshold point of the
receiver.
03/P/22
Содержание RPU Link
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